The invention concerns a method for automatically controlling the speed of a ship.
The power requirement of an inland ship propulsion system depends primarily on the draft, the water level and the running speed. The navigator predetermines the course by way points, and the desired arrival time is set. A power plant controller then uses the setpoint values to compute a constant desired average speed.
To maintain a time program predetermined by the navigator with the smallest possible amount of fuel consumption, DE 32 30 621 C2 proposes that the ship's speed be monitored by means of a cascaded closed-loop control system, in which a closed-loop control system for the ship's speed constitutes the external closed-loop control system. The correcting variable of the closed-loop control system for the ship's speed is simultaneously the reference input of a subordinate, internal closed loop control system for the engine speed. The ground speed is measured as the controlled variable of the closed-loop control system for the ship's speed. The reference input of the closed-loop control system for the ship's speed, i.e., the set ship's speed, is adapted to external influences, for example, to the contours of the shore panorama via a radar transmitter-receiver or to upstream or downstream travel. With this type of structure of the closed-loop control system, the suction of the ship with too little water under the hull causes a lower ship's actual speed and thus brings about a corresponding ship's speed control deviation. The ships speed controller responds to this by increasing the engine set speed. An increased engine set speed in turn causes increased fuel consumption, so that the automatic control system is not yet optimal in all operating states.